These aren't exactly a piece of the True Cross, but they'll do in a pinch:

The Eye of St. Tsenman Tsan, Major Relic
Minor Powers: ESP (30' range, 3 times/day), Detect Charm (3 times/day)
Major Powers: Cure Disease (by touch), X-Ray Vision (2 times/day), Charm Person (7 times/week)
Drawbacks: Item is unable to function in environments colder than freezing.

The Book of the Abyss, Major Artifact
Minor Powers: Zombie Animation (1 time/week), ESP (40' range, 3 times/day), Cure Light Wounds (7 times/week), Clairvoyance
Major Powers: True Seeing (1 time/day), Teleport (no error, 2 times/day), Slow (1 time/day), Transmute Rock to Mud (2 times/day), Haste (1 time/day), Disintegrate (1 time/day), Paralyzation (by touch)
Prime Power(s): Cacodemon-like power (summons a Demon Lord, Arch-devil, or Nycadaemon, 1 time/month). User has limited omniscience and may request the DM to answer 1 question per game day (answer is given with limitations set by DMs discretion)
Drawbacks: Possessor's hair turns white. Lose 4 CHA points for 2 days when major power used. The Book is powerless against and hates 3 species of creatures, and when within 10' of any such creatures it forces its possessor to attack. Lose 1 point of WIS permanently when the book is first read. The relic must be devoured by the Chromatic Dragon TIAMAT (The Queen of Evil Dragons) (MM p.32) to destroy it.

The Hair of Torctgeld, Minor Relic
Minor Powers: Protection +2 (when held)
Major Powers: Speak with Monster (2 times/day), Word of Recall (1 time/day)
Drawbacks: Item causes its possessor to experience terrible nightmares.

The 4 Toes of St. Endi Shapi, Minor Relic
Minor Powers: Speak with plants (7 times/week), Levitate (when held and ordered, 3 times/day)
Clairvoyance (when touched to the eyes)
Major Powers: Wizard Eye (2 times/day), Confusion (1 time/day)
Drawbacks: Wart appears on possessor's nose

The Eon Stone, Minor Artifact
Minor Powers: Fly (when held and ordered, 1 time/day), Ultravision (when held)
Major Powers: Cause Serious Wounds (by touch), Disintegrate (1 time/day), Lightning Bolt (9HD,2 times/day), Paralyzation (by touch)
Prime Power: DEX permanently raised to 19 upon command word
Drawbacks: Possessor loses interest in sex. Item is immune to electricity or magical lightning. Capricious alignment change when the primary power is used. User becomes ethereal whenever any major power of the item is activated, and there is a 5% cumulative chance that he or she will thereafter become ethereal whenever a stress (combat, life-or-death, difficult problem involving user's decision) situation exists; the ethereal state lasts until stress is removed. The relic must be exposed to the Ray of Eternal Shrinking to destroy it.

The Seed of Angmelcelme, Major Relic
Minor Powers: Protection +2 (when held), Shield (when held, upon command, 3 times/day)
Major Powers: Dispel Magic upon command (2 times/day)
Drawbacks: Small fires (torches, et.al.) extinguished when major power used, Item will not work if its wearer is clad in metal armor.

The Breath of Dunatis, Major Relic
Minor Powers: Possessor Immune to Disease
Major Powers: True Seeing (1 time/day)
Drawbacks: Touch of possessor kills green plants, Small items of wood rot from possessor's touch in 17 days

Armor of Ushas, Minor Artifact
Minor Powers: Ultravision (when worn), Wearer immune to Magic Missiles, Charm or Hold spells
Major Powers: Exorcise (1 time/month), Slow (1 time/day), Wall of Ice (2 times/day), Wall of Fire (2 times/day)
Prime Power: Bones/exoskeleton/cartilage of opponent turned to jelly (1 time/day)
Drawbacks: Touch of possessor kills green plants, Lose 1 point of STR permanently when first worn. Body rot is 10 percent cumulative likely whenever a primary power is used, and part of the body is lost permanently. Fear reaction possible in any creature within 20' of the item whenever a major or primary power is used; all, including possessor, must save versus magic or flee in panic. The relic must be baptized in the the River Lethe to destroy it.

St. Nema Sine's Ashes, Major Relic
Minor Powers: Raise Dead (1 figure by touch, 1 time/week)
Major Powers: Titan strength (2 turns)
Drawbacks: Item will not function underground at depths greater than 100' below the surface.

The Gauntlet of the Demigod, Major Artifact
Minor Powers: Possessor need neither eat nor drink (up to 1 week). Remove Fear (by touch). Sanctuary (when worn, 1 time/day). Possessor Immune to Disease. Hypnotic Pattern (3 times/day)
Major Powers: Weapon dmg +2. Charm Person (7 times/week). Cure Blindness (by touch). Dispel Magic upon command (2 times/day). Transmute Rock to Mud (2 times/day). Titan strength (2 turns). X-Ray Vision (2 times/day)
Prime Power(s): Wish (1 time/day). Vanish (2 times/day)
Drawbacks: Item works erratically; there is a 5 percent chance when its powers are utilized that it shorts itself out and is unusable for 24 hours. Saving throws versus magic are at -1. User shrinks 1/4" each time primary power is used. User has a poison touch which requires that humans and man-sized humanoids (but not undead) save versus poison whenever touched . The relic must be exposed to the light of the Moon on the first day of the lunar New Year to destroy it.